This invention relates to methods for concurrently performing multiple biological chip assays. The invention therefore relates to diverse fields impacted by the nature of molecular interaction, including chemistry, biology, medicine and diagnostics.
New technology, called VLSIPS.TM., has enabled the production of chips smaller than a thumbnail that contain hundreds of thousands or more of different molecular probes. These biological chips or arrays have probes arranged in arrays, each probe assigned a specific location. Biological chips have been produced in which each location has a scale of, for example, ten microns. The chips can be used to determine whether target molecules interact with any of the probes on the chip. After exposing the array to target molecules under selected test conditions, scanning devices can examine each location in the array and determine whether a target molecule has interacted with the probe at that location.
Biological chips or arrays are useful in a variety of screening techniques for obtaining information about either the probes or the target molecules. For example, a library of peptides can be used as probes to screen for drugs. The peptides can be exposed to a receptor, and those probes that bind to the receptor can be identified.
Arrays of nucleic acid probes can be used to extract sequence information from, for example, nucleic acid samples. The samples are exposed to the probes under conditions that allow hybridization. The arrays are then scanned to determine to which probes the sample molecules have hybridized. One can obtain sequence information by careful probe selection and using algorithms to compare patterns of hybridization and non-hybridization. This method is useful for sequencing nucleic acids, as well as sequence checking. For example, the method is useful in diagnostic screening for genetic diseases or for the presence and/or identity of a particular pathogen or a strain of pathogen. For example, there are various strains of HIV, the virus that causes AIDS. Some of them have become resistant to current AIDS therapies. Diagnosticians can use DNA arrays to examine a nucleic acid sample from the virus to determine what strain it belongs to.
Currently, chips are treated individually, from the step of exposure to the target molecules to scanning. These methods yield exquisitely detailed information. However, they are not adapted for handling multiple samples simultaneously. The ability to do so would be advantageous in settings in which large amounts of information are required quickly, such as in clinical diagnostic laboratories or in large-scale undertakings such as the Human Genome Project.